Coffee culture

What is Coffee Channeling? Why Does Espresso Experience Channeling? What Are the Causes and How to Solve It?

Published: 2026-01-27 Author: FrontStreet Coffee
Last Updated: 2026/01/27, FrontStreet Coffee frequently mentions "channeling" in our articles because during the coffee extraction process, channeling negatively impacts coffee flavor. And it occurs quite frequently! So today, FrontStreet Coffee will share with you what channeling actually is and how to address it!

Understanding Channeling in Coffee Extraction

FrontStreet Coffee often mentions "channeling" in articles because it can have negative effects on coffee flavor during the extraction process. And it happens quite frequently! So today, FrontStreet Coffee will share what channeling actually is and how to prevent it.

What is Channeling?

Channeling in coffee refers to uneven distribution of hot water during extraction. To brew delicious coffee, besides ensuring stable parameters, we need hot water to evenly penetrate most of the coffee grounds so they can release appropriate amounts of flavor compounds.

Water flowing through coffee grounds

In ideal conditions, water would naturally flow downward due to gravity, allowing even extraction of coffee grounds. However, water, being inert, prefers to find the easiest paths to flow through. What does this mean? It's like watering dry, cracked land - the water will concentrate and flow through the cracks. When you apply this principle to hot water extracting coffee, it becomes quite clear!

Water channeling demonstration

This leads to areas where water concentrates, causing over-extraction and dissolving undesirable bitter compounds. Meanwhile, areas without concentrated water flow become under-extracted, lacking sufficient dissolved substances. These unsaturated coffee liquids affect the entire cup, resulting in insufficient strength and flavor. Espresso extraction is most affected by channeling because it requires hot water to dissolve two-thirds of the soluble compounds from a coffee puck in a very short time. All extraction parameters operate at high efficiency. If channeling occurs under such extreme conditions, it significantly impacts the coffee's flavor.

Espresso extraction process

How to Identify Channeling

Although we can't directly see how hot water flows during extraction, we don't need to. The manifestations of channeling are quite obvious. Even before tasting the coffee, you can identify whether channeling has occurred through the following signs.

1. Holes in the Coffee Puck

The cause of channeling is uneven distribution of coffee grounds in the puck, creating inconsistent water flow resistance in different areas. This causes hot water to concentrate and break through areas of weak resistance. When channeling occurs during extraction, we can see numerous dense holes on the surface of the removed coffee puck - these are the "channels" created by hot water! We call this phenomenon "perforation."

Coffee puck with channeling holes

2. Splashing During Extraction

Using a bottomless portafilter helps us observe this phenomenon more directly, as bottomless portafilters were invented specifically for this purpose. Therefore, if we use a bottomless portafilter for extraction and channeling occurs during the process, there's a high probability of splashing as the espresso is released, as shown in the image below.

Espresso splashing from channeling

How to Solve Channeling

Since channeling is primarily caused by uneven distribution of coffee grounds, we only need to optimize the distribution process. FrontStreet Coffee detailed the important aspects of distribution in the article "The Importance of Proper Coffee Distribution" - you can click the blue text to jump to the detailed explanation.

Proper coffee distribution technique

Finally, FrontStreet Coffee suggests that those wearing light-colored clothes maintain a certain distance during bottomless portafilter extraction. Otherwise, channeling won't just make your espresso "complex" in flavor - it might affect your wardrobe too!

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473

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